The present invention relates to the general field of stators for a compressor in a turbine engine such as an airplane turboprop or turbojet.
A compressor in a turbine engine is made up of a plurality of compression stages, each comprising both an annular row of moving blades mounted on a shaft of the engine, and also a stator mounted on an outer annular casing of the engine.
A compressor stator may be constituted by a ring, or it may be sectorized (i.e. made up of a plurality of angular sectors connected circumferentially end to end around the longitudinal axis of the compressor). Throughout the present application, the term “stator angular sector” (or “stator sector” to be more concise) is used to mean any angular sector of a stator and presenting an angle that is less than or equal to 360°.
Each stator sector has an outer shroud and an inner shroud that are arranged coaxially one in the other, together with one (or more) vane(s) extending radially between the shrouds and connected thereto via its (their) radial ends.
By way of example, each stator angular sector is mounted in the outer annular casing of the engine by means of respective mounting tabs provided at each axial end of the outer shroud of said sector for the purpose of being engaged in corresponding annular grooves in the casing.
In operation, such a stator sector is subjected to high levels of mechanical stress, both static stress and vibrational stress.
In prior art stators in which the leading and trailing edges of the vanes are connected to portions of the outer shroud that are very thick and very stiff, these mechanical stresses are essentially taken up by the leading edge and trailing edge zones connected to the outer shroud of the stator sector. Since these connection zones are thin and not very strong, there is a risk of the leading and trailing edges being damaged or even destroyed.
Document EP 1 811 131 proposes reducing the stress on the leading and trailing edges of the vanes of stator sectors by reducing the stiffness of the connections of the stator vanes in order to optimize the transition of forces from the vanes to the outer shroud. For that purpose, the leading and/or trailing edges of the vanes are connected to zones of the outer shroud that are less rigid than the zones of the outer shroud that are connected in particular to the mounting tabs. Nevertheless, that proposal does not provide satisfactory damping of the leading and trailing edges of the vanes in the connection zones where they are connected to the outer shroud, for the purpose of effectively avoiding the vanes breaking as a result of vibration.